aaudio: clarify autodocs

    /**

     * Extending battery life is most important.

     *

     * This mode is not supported in input streams.

     * Mode NONE will be used if this is requested.

     */

            AAUDIO_PERFORMANCE_MODE_POWER_SAVING,

 * For an input stream, this function should read and process numFrames of data

 * from the audioData buffer.

 *

 * Note that this callback function should be considered a "real-time" function.

 * The audio data is passed through the buffer. So do NOT call AAudioStream_read() or

 * AAudioStream_write() on the stream that is making the callback.

 *

 * Note that numFrames can vary unless AAudioStreamBuilder_setFramesPerDataCallback()

 * is called.

 *

 * Also note that this callback function should be considered a "real-time" function.

 * It must not do anything that could cause an unbounded delay because that can cause the

 * audio to glitch or pop.

 *

 * <li>any network operations such as streaming</li>

 * <li>use any mutexes or other synchronization primitives</li>

 * <li>sleep</li>

 * <li>stop or close the stream</li>

 * </ul>

 *

 * If you need to move data, eg. MIDI commands, in or out of the callback function then

 * @param stream reference provided by AAudioStreamBuilder_openStream()

 * @param userData the same address that was passed to AAudioStreamBuilder_setCallback()

 * @param audioData a pointer to the audio data

 * @param numFrames the number of frames to be processed

 * @param numFrames the number of frames to be processed, which can vary

 * @return AAUDIO_CALLBACK_RESULT_*

 */

typedef aaudio_data_callback_result_t (*AAudioStream_dataCallback)(

        aaudio_result_t error);

/**

 * Request that AAudio call this functions if any error occurs on a callback thread.

 * Request that AAudio call this function if any error occurs or the stream is disconnected.

 *

 * It will be called, for example, if a headset or a USB device is unplugged causing the stream's

 * device to be unavailable.

 * In response, this function could signal or launch another thread to reopen a

 * stream on another device. Do not reopen the stream in this callback.

 * device to be unavailable or "disconnected".

 * Another possible cause of error would be a timeout or an unanticipated internal error.

 *

 * This will not be called because of actions by the application, such as stopping

 * or closing a stream.

 * In response, this function should signal or create another thread to stop

 * and close this stream. The other thread could then reopen a stream on another device.

 * Do not stop or close the stream, or reopen the new stream, directly from this callback.

 *

 * Another possible cause of error would be a timeout or an unanticipated internal error.

 * This callback will not be called because of actions by the application, such as stopping

 * or closing a stream.

 *

 * Note that the AAudio callbacks will never be called simultaneously from multiple threads.

 *

 * This will update the current client state.

 *

 * <pre><code>

 * aaudio_stream_state_t currentState;

 * aaudio_result_t result = AAudioStream_getState(stream, &currentState);

 * while (result == AAUDIO_OK && currentState != AAUDIO_STREAM_STATE_PAUSING) {

 * aaudio_result_t result = AAUDIO_OK;

 * aaudio_stream_state_t currentState = AAudioStream_getState(stream);

 * aaudio_stream_state_t inputState = currentState;

 * while (result == AAUDIO_OK && currentState != AAUDIO_STREAM_STATE_PAUSED) {

 *     result = AAudioStream_waitForStateChange(

 *                                   stream, currentState, &currentState, MY_TIMEOUT_NANOS);

 *                                   stream, inputState, &currentState, MY_TIMEOUT_NANOS);

 *     inputState = currentState;

 * }

 * </code></pre>

 *

 * This call can be used if the application needs to know the value of numFrames before

 * the stream is started. This is not normally necessary.

 *

 * If a specific size was requested by calling AAudioStreamBuilder_setCallbackSizeInFrames()

 * If a specific size was requested by calling AAudioStreamBuilder_setFramesPerDataCallback()

 * then this will be the same size.

 *

 * If AAudioStreamBuilder_setCallbackSizeInFrames() was not called then this will

 * If AAudioStreamBuilder_setFramesPerDataCallback() was not called then this will

 * return the size chosen by AAudio, or AAUDIO_UNSPECIFIED.

 *

 * AAUDIO_UNSPECIFIED indicates that the callback buffer size for this stream